December 23, 2006, 10:56 AM CT

Beaked Whales Observed

On the 17th of December, Meike Scheidat & Linn Lehnert, the whale watchers on board of Polarstern, made a remarkable cetaceans sighting: Four Arnoux's Beaked Whales (Berardius arnuxii), observed from the helicopter.

The Arnoux's Beaked Whales is one of the least known species of the Beaked Whales family (Ziphidae), itself poorly known in general. Arnoux's is one of the biggest species amongst beaked whales. The ones observed were probably 9 metre long. These deep-sea feeding whales are especially sensitive to underwater acoustic disturbances. The pictures showed a whole array of scars on their skin, which are already under investigation. Some of these scars could have been inflicted by orcas, their potential predators, or by squids, their most common preys, as proposed by Elaina Jorgensen one of our cephalopod specialist onboard. Other scars could be caused by cookie-cutter sharks, which would imply big migration between the subtropical waters where these sharks are found and the ice-edge (64 degree 06 S) where they were observed.

Supply of German Neumayer station

After crossing the Atlantic and the sea ice of the Atka Bay Polarstern supplied the German research station Neumayer on the Ekstrom Ice Shelf with food and fuel. Helicopters brought up hoses to refill eight 20,000-liter tanks with diesel fuel. The tanks were sitting on sledges ready for later transportation to the station by Caterpillars. The cargo had to be loaded on a secure area on the sea ice as ice conditions did not allow Polarstern to enter the "ice port" right next to the shelf edge.........

Posted by: Kelly      Read more         Source

December 23, 2006, 9:00 AM CT

Giraffe: Winning by a neck

Whenever I go to a zoo, I stand in front of the giraffes and watch with awe and respect at these wonderful creatures. I always consider them to be an extreme example of natural selection. I read this article and thought it would be worth mentioning in our blog.

The giraffe's elongated neck has long been used in textbooks as an illustration of evolution by natural selection, but this common example has received very little experimental attention. In the recent issue of the American Naturalist, scientists at the Mammal Research Institute in the Department of Zoology and Entomology at the University of Pretoria tested whether foraging competition with shorter herbivores could explain why giraffes feed mostly on leaves high in trees, despite being able to feed at lower levels as well.

"This [study] provides the first real experimental evidence that the long neck of the giraffe might have evolved as a consequence of competition, which provides support for a previously untested textbook example of natural selection," says Elissa Cameron (University of Pretoria), who coauthored the study with Johan du Toit (University of Pretoria and Utah State University).

Giraffes are well known for their unusual height, and they generally feed high in the tree canopy, above the height other herbivores can reach. Giraffes receive more leaves per bite by foraging high in the tree, but it's unclear whether this is caused by competition -- smaller browsers eating some of the leaves at lower heights -- or if more leaves grow at higher levels.........

Posted by: Kelly      Read more         Source

December 20, 2006, 7:01 PM CT

Tadpoles Fly To Puerto Rico

While a number of of New York's snow birds head south to Puerto Rico for time in the sun, a recent batch of first-time fliers--born and raised in the city--are heading down for a different reason: to save their own species. And tadpoles generally do not fly, unless they are part of a reintroduction program to save the Puerto Rican crested toad, as per the Wildlife Conservation Society (WCS), which has joined an ongoing effort to save the island's only native toad.

Specifically, animal husbandry experts from WCS have successfully reared nearly 500 tadpoles at the Central Park Zoo and recently released them in Puerto Rico's Guanica State Forest.

"The release went well, and we're hoping that this new generation of toads can help secure a future for this species" said Bruce Foster, Collections Manager for WCS' Central Park Zoo, where he and other curatorial staff successfully reared some 475 healthy tadpoles for the reintroduction effort. "Puerto Rico is an island of great natural beauty, and protecting the natural inhabitants of the island is an important part of preserving that beauty".

Foster flew down to Puerto Rico with his precious cargo and made the rendezvous with other participants at the release site: a manmade pond in Guanica State Forest. Combined with contributions from the Fort Worth Zoo, the Buffalo Zoo, and the Sedgwick County Zoo, a total of 2,700 tadpoles were released into the pond. The project is also supported by the U.S. Fish and Wildlife Service, and the Puerto Rican Department of Natural Resources.........

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December 20, 2006, 5:09 AM CT

Climate Change And Endangered Naked Carp

Forthcoming in the January/February 2007 issue of Physiological and Biochemical Zoology, a groundbreaking study reveals an unanticipated way freshwater fish may respond to water diversion and climate change. Endangered naked carp migrate annually between freshwater rivers, where they spawn, and a lake in Western China, where they feed and grow. However, Lake Qinghai is drying up and becoming increasingly more saline--leading to surprising adjustments to the carps' metabolic rate.

Naked carp take seven to ten years to reach reproductive size. Eventhough historically abundant, overfishing and destruction of spawning habitat through dam-building caused the species to become endangered during the 1990s. Diversion of water for agriculture from the lake has been compounded by climate change, leading to a decline in water level in the lake of 1012 cm per year during the past fifty years (see accompanying image).

However, Chris M. Wood (McMaster University) and coauthors observed that naked carp respond to the increased salinity of the lake water in a surprising way--by taking a "metabolic holiday." In the first forty-eight hours after transitioning from the freshwater river system to lake water, the carps' oxygen consumption falls --eventually reaching just 60 percent of that in river fish.........

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December 20, 2006, 4:23 AM CT

Are Nanoparticles Viable Living Forms?

Scientists at Mayo Clinic have successfully isolated nanoparticles from human kidney stones in cell cultures and have isolated proteins, RNA and DNA that appear to be linked to nanoparticles. The findings, which appear in the recent issue of the Journal of Investigative Medicine, are significant because it is one step closer in solving the mystery of whether nanoparticles are viable living forms that can lead to disease -- in this case, kidney stones.

Kidney stones are linked to pathologic calcification, the process in which organs and blood vessels become clogged with calcium deposits that can damage major organs like the heart and kidneys. What causes calcium deposits to build up is not entirely known. Medical researchers at Mayo Clinic are studying calcification at the molecular level in an effort to determine how this phenomenon occurs.

There is a growing body of scientific evidence that links calcification to the presence of nanosized particles, particles so small that some researchers question whether a nanoparticle can live and if so, play a viable role in the development of kidney stones.

The presence of proteins, RNA and DNA does not prove that nanoparticles are viable living forms because a genetic signature has not been identified, says the study's author John Lieske, M.D., a nephrologist with Mayo Clinic. A genetic signature would prove that nanoparticles are indeed living forms that replicate and can cause disease.........

Posted by: Janet      Permalink         Source

December 20, 2006, 4:16 AM CT

Language of the Nerve Cells

UC San Diego biologists have shown that the chemical language with which neurons communicate depends on the pattern of electrical activity in the developing nervous system. The findings suggest that modification of nerve activity could have potential as a treatment for a wide range of brain disorders.

In the study, published this week in the early on-line edition of the journal Proceedings of the National Academy of Sciences, the biologists showed that, contrary to the prevailing viewpoint, neurotransmitters-the chemical language of nerve cells-and receptors-the proteins that receive and respond to neurotransmitters-are not specified by a rigid genetic program. Altering nerve activity during development determines the "mother tongue" nerve cells use to communicate. The study will appear in the print edition of PNAS on January 2.

"Most cognitive disorders, such as depression, schizophrenia and Parkinson's disease, involve problems with neurotransmitters or neurotransmitter receptors," said Nicholas Spitzer, a professor of biology and the senior author of the study. "If modifying electrical activity in the adult brain can alter neurotransmitters and receptors similarly to the way we have discovered in the developing frog nervous system, it could provide a promising approach to treating these disorders".........

Posted by: Janet      Permalink         Source

December 18, 2006, 9:30 PM CT

How To Avoid A Bat

Current understanding of the co-evolution of bats and moths has been thrown into question following new research reported today in Current Biology.

Dr James Windmill from the University of Bristol, UK, has shown how the Yellow Underwing moth changes its sensitivity to a bat's calls when the moth is being chased. And in case there is another attack, the moth's ear remain tuned in for several minutes after the calls stop.

Dr Windmill said: "Because the moth cleverly tunes its ear to enhance its detection of bats, we must now question whether the bat in turn modifies its calls to avoid detection by the moth. In view of the vast diversity of bat calls, this is only to be expected.

"To date, this phenomenon has not been reported for insects or, in fact, for any other hearing system in the animal kingdom. These findings change our understanding of the co-evolution of bats and moths and have implications for the hearing of a number of other animals".

It has been known for over 50 years that moths can hear the ultrasonic hunting calls of their nocturnal predator, the bat. Previously it was thought that these ears were only partially sensitive to the sound frequencies usually used by bats and that bats would make their hunting calls inaudible to moths.........

Posted by: Kelly      Permalink         Source

December 18, 2006, 9:26 PM CT

Flexibility In Flight Behaviour In Marine Iguanas

Who of us has not dreamt of living on an island? Apparently, island life has certain advantages. This is also true for the marine iguanas. For millions of years they have lived without natural predators. In the course of evolution they have become excessively tame. Hundreds of reptiles doze, spread-eagled, on black lava rocks, soaking up the sun - behaviour that would be unthinkable in an environment with predators, where reptiles are persistently exposed to the threat of being devoured by others.

The absence of predators may lead to adaptations in the behaviour of insular animals. Over a longer evolutionary period, birds for example can lose their ability to fly. This would greatly reduce their ability to escape should new predators appear. In contrast to such "hard wired" traits, however, behavioural patterns should be significantly more flexible. In programmes introducing tame species into the wild, animals are trained to recognise and cope with predators. But in most cases it is very difficult to predict the flexibility in behaviour because little is known about the underlying physiological mechanisms that control behaviour such as flight.

The scientist around Thomas Rodl from the Max Planck Institute for Ornithology visited the Galápagos Islands for field studies from December 2003 until January 2004 and again in March 2005, using the research platform of the Max Planck Society. The islands in the Pacific Ocean continue to be a magnet for evolutionary biologists. Nowhere else is it possible to observe such a variety of different adaptation strategies in such a relatively small number of species. However, it is not only researchers who are drawn to the island; increasingly tourists have also discovered this unique archipelago. In 2005, approx. 126,000 people descended on the island, and the trend is rising. And this causes problems. Not only do tourists disturb the a number of animals living on the Galápagos Islands; they also introduce alien animal and plant species which are causing great damage to local flora and fauna.........

Posted by: Kelly      Permalink         Source

December 18, 2006, 9:19 PM CT

Top 10 Myths About Evolution

Though the United States is the world leader in science and technology, a number of of its citizens display a shocking ignorance regarding basic scientific facts. Recent surveys have revealed that only about half of Americans realize that humans have never lived side by side with dinosaurs, and about the same number reject the idea that humans developed from earlier species of animals. This lack of knowledge in the face of overwhelming scientific evidence for evolution springs from many negative influences in contemporary society: poor secondary education in some regions of the country, misinformation in the mass media, and deliberate obfuscation by supporters of Creationism and Intelligent Design.

In The Top 10 Myths About Evolution, educators Cameron M. Smith and Charles Sullivan clearly dispel the ten most common myths about evolution that continue to mislead average Americans. Using a refreshing, jargon-free style, they set the record straight on claims that evolution is "just a theory," that Darwinian explanations of life undercut morality, that Intelligent Design is a legitimate alternative to conventional science, that humans come from chimpanzees, and six other popular but erroneous notions.

Smith and Sullivan's reader-friendly, solidly researched text will serve as an important tool, both for teachers and laypersons seeking accurate information about evolution.........

Posted by: Kelly      Permalink         Source

December 18, 2006, 9:15 PM CT

Biological Clock For Smell In Mice

Biologists at Washington University in St. Louis have discovered a large biological clock in the smelling center of mice brains and have revealed that the sense of smell for mice is stronger at night, peaking in evening hours and waning during day light hours.

A team led by Erik Herzog, Ph.D., Washington University associate professor of Biology in Arts & Sciences, discovered the clock in the olfactory bulb, the brain center that aids the mouse in detecting odors.

The olfaction biological clock is hundreds of times larger than the known biological clock called the suprachiasmatic nucleus (SCN), located at the base of the brain right on top of where the optic nerves cross each other. Cells in both the SCN and the olfactory bulb keep 24-hour time and are normally highly sychronized to each other and environmental cycles of day-night.

"It's been a question for some time whether the SCN functions as the only biological clock," said Herzog. "One wouldn't believe that the ability to smell would cycle, but that's what we show.

" I think now that the SCN is like the atomic clock, important for keeping central time, and then there are all of these peripheral clocks - for timing tasks like sleep-wake, vigilance, digestion, olfaction, hearing, touch and vision, though not all yet found. It may be that the peripheral clocks are like individual wristwatches that we must periodically reset."........

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